Semiconductor device and method of fabricating the same

ABSTRACT

A semiconductor device includes a substrate, a conductive pattern, a side spacer, and an air gap. The substrate includes an interlayer insulating layer and a trench penetrating the interlayer insulating layer. The conductive pattern is disposed within the trench of the substrate. The side spacer is disposed within the trench. The side spacer covers an upper side surface of the conductive pattern. The air gap is disposed within the trench. The air gap is bounded by a sidewall of the trench, the side spacer, and a lower side surface of the conductive pattern. A level of a bottom surface of the conductive pattern is lower than a level of bottom surfaces of the side spacer.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. §119 to Korean PatentApplication No. 10-2013-0026388, filed on Mar. 12, 2013 in the KoreanIntellectual Property Office, the disclosure of which is herebyincorporated by reference in its entirety.

TECHNICAL FIELD

The present inventive concept relates to a semiconductor device and amethod of fabricating the same.

DISCUSSION OF RELATED ART

Conductive patterns serve to connect various elements incorporated insemiconductor devices. Capacitance between the conductive patterns maydelay a signal propagation. As semiconductor devices are highlyintegrated, such signal delay decreases the performance thereof.

SUMMARY

According to an exemplary embodiment of the inventive concept, asemiconductor device includes a semiconductor substrate, a lowerconductive pattern, an interlayer insulating layer, an upper conductivepattern, a side spacer, and an air gap. The lower conductive pattern isdisposed on the semiconductor substrate. The interlayer insulating layeris disposed on the semiconductor substrate. The interlayer insulatinglayer includes an upper penetrating hole partially exposing a topsurface of the lower conductive pattern. The upper conductive pattern isdisposed within the upper penetrating hole and is disposed on the topsurface of the lower conductive pattern. The upper conductive pattern iselectrically connected to the lower conductive pattern. The side spaceris disposed within the upper penetrating hole. The side spacer covers anupper side surface of the upper conductive pattern. The air gap isdisposed within the upper penetrating hole. The air gap is bounded by asidewall of the upper penetrating hole, the side spacer, part of the topsurface of the lower conductive pattern, and a lower side surface of theupper conductive pattern.

According to an exemplary embodiment of the inventive concept, asemiconductor device includes a substrate, a conductive pattern, a sidespacer, and an air gap. The substrate includes an interlayer insulatinglayer and a trench penetrating the interlayer insulating layer. Theconductive pattern is disposed within the trench of the substrate. Theside spacer is disposed within the trench. The side spacer covers anupper side surface of the conductive pattern. The air gap is disposedwithin the trench. The air gap is bounded by a sidewall of the trench,the side spacer, and a lower side surface of the conductive pattern. Alevel of a bottom surface of the conductive pattern is lower than alevel of bottom surfaces of the side spacer.

According to an exemplary embodiment of the inventive concept, asemiconductor device includes a semiconductor substrate, an interlayerinsulating layer, a conductive pattern, an etch stop layer, a sidespacer, and an air gap. The interlayer insulating layer is disposed onthe semiconductor substrate. The interlayer insulating layer includes atrench penetrating the interlayer insulating layer. The conductivepattern is disposed within the trench. A bottom surface of theconductive pattern being contact with a bottom surface of the trench.The etch stop layer is disposed on the conductive pattern. The etch stoplayer covers the trench. The side spacer covers a side surface of theconductive pattern. The side spacer is spaced from the interlayerinsulating layer. The air gap is bounded by the interlayer insulatinglayer, the conductive pattern, the etch stop layer and the side spacer.A bottom surface of the side spacer is spaced from the bottom surface ofthe trench.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the inventive concept will become moreapparent by describing in detail exemplary an exemplary embodimentthereof with reference to the accompanying drawings of which:

FIG. 1 is a cross-sectional view of a semiconductor device according toan exemplary embodiment of the inventive concept;

FIG. 2 is a cross-sectional view of a semiconductor device according toan exemplary embodiment of the inventive concept;

FIG. 3 is a cross-sectional view of a semiconductor device according toan exemplary embodiment of the inventive concept;

FIGS. 4A through 4R are cross-sectional views illustrating sequentialoperations of a method of fabricating a semiconductor device accordingto an exemplary embodiment of the inventive concept;

FIGS. 5A through 5G are cross-sectional views illustrating sequentialoperations of a method of fabricating a semiconductor device accordingto an exemplary embodiment of the inventive concept;

FIG. 6 is a diagram of a semiconductor module including a semiconductordevice according to an exemplary embodiment of the inventive concept;

FIG. 7 is a diagram of a mobile system including a semiconductor deviceaccording to an exemplary embodiment of the inventive concept;

FIG. 8 is a diagram of a mobile device including a semiconductor deviceaccording to an exemplary embodiment of the inventive concept; and

FIG. 9 is a diagram of an electronic system including a semiconductordevice according to an exemplary embodiment of the inventive concept.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Exemplary an exemplary embodiment of the inventive concept will bedescribed below in detail with reference to the accompanying drawings.However, the inventive concept may be embodied in different forms andshould not be construed as limited to the exemplary embodiment set forthherein. In the drawings, the thickness of layers and regions may beexaggerated for clarity. It will also be understood that when a layer isreferred to as being “on” another layer or substrate, it may be directlyon the other layer or substrate, or intervening layers may also bepresent. Like reference numerals may refer to the like elementsthroughout the specification and drawings.

FIG. 1 is a cross-sectional view of a semiconductor device 100 aaccording to an exemplary embodiment of the inventive concept.

Referring to FIG. 1, a semiconductor device 100 a includes asemiconductor substrate 100, a lower interlayer insulating layer 110, alower conductive pattern 120 p, a lower etch stop layer 130, an upperinterlayer insulating layer 140, side spacers 160 s, an upper conductivepattern 170 p, an upper etch stop layer 180, and an air gap 190 a.

The semiconductor substrate 100 may include a silicon wafer or asilicon-on-insulator (SOI) substrate. The lower interlayer insulatinglayer 110 is disposed on the semiconductor substrate 100. Variouselements may be disposed between the semiconductor substrate 100 and thelower interlayer insulating layer 110. The lower interlayer insulatinglayer 110 may cover the various elements disposed on the semiconductorsubstrate 100. The lower interlayer insulating layer 110 may includetetraethyl orthosilicate (TEOS).

The lower conductive pattern 120 p is disposed in the lower interlayerinsulating layer 110. The lower conductive pattern 120 p may beelectrically connected to at least one of various elements disposedbetween the semiconductor substrate 100 and the lower interlayerinsulating layer 110. The lower conductive pattern 120 p penetrates thelower interlayer insulating layer 110. A level of a top surface of thelower conductive pattern 120 p is substantially the same as a level of atop surface of the lower interlayer insulating layer 110. The lowerinterlayer insulating layer 110 surrounds a side surface of the lowerconductive pattern 120 p.

The lower conductive pattern 120 p may include a conductive material.For example, the lower conductive pattern 120 p may include tungsten(W).

The lower conductive pattern 120 p includes a first recess region 121 rand a second recess region 122 r.

The first recess region 121 r is disposed in the top surface of thelower conductive pattern 120 p. A maximum horizontal width of the firstrecess region 121 r is less than a horizontal width of the top surfaceof the lower conductive pattern 120 p. A level of a bottom surface ofthe first recess region 121 r is lower than a level of the top surfaceof the lower conductive pattern 120 p. A level of the bottom surface ofthe first recess region 121 r is lower than a level of the top surfaceof the lower interlayer insulating layer 110.

The second recess region 122 r is disposed in the top surface of thelower conductive pattern 120 p. The second recess region 122 r isdisposed in the first recess region 121 r. A maximum horizontal width ofthe second recess region 122 r is less than the maximum horizontal widthof the first recess region 121 r. A horizontal width of the secondrecess region 122 r in the bottom surface of the first recess region 121r is less than a horizontal width of the bottom surface of the firstrecess region 121 r. A level of a bottom surface of the second recessregion 122 r is lower than a level of the bottom surface of the firstrecess region 121 r. A sidewall of the second recess region 122 r neednot be parallel to a sidewall of the first recess region 121 r.

The lower etch stop layer 130 is disposed on the lower interlayerinsulating layer 110. The lower etch stop layer 130 is in contact withthe top surface of the lower interlayer insulating layer 110.

The lower etch stop layer 130 may have a different etch rate from thelower interlayer insulating layer 110. The lower etch stop layer 130 mayhave etch selectivity with respect to the lower interlayer insulatinglayer 110. The lower etch stop layer 130 may be harder than the lowerinterlayer insulating layer 110. For instance, the lower etch stop layer130 may include silicon nitride (SiN) or silicon carbon nitride (SiCN).

The lower etch stop layer 130 includes a lower penetrating hole 130 h.The lower penetrating hole 130 h penetrates the lower etch stop layer130. The lower penetrating hole 130 h partially exposes the top surfaceof the lower conductive pattern 120 p. The lower penetrating hole 130 hexposes the first recess region 121 r of the lower conductive pattern120 p.

A sidewall of the lower penetrating hole 130 h corresponds to anextension line of the sidewall of the first recess region 121 r. Ahorizontal width of the lower penetrating hole 130 h measured at abottom surface of the lower etch stop layer 130 is substantially equalto a horizontal width of the first recess region 121 r measured at thetop surface of the lower conductive pattern 120 p. A horizontal width ofthe lower penetrating hole 130 h measured at the top surface of thelower interlayer insulating layer 110 is substantially equal to ahorizontal width of the first recess region 121 r measured at the topsurface of the lower interlayer insulating layer 110.

The upper interlayer insulating layer 140 is disposed on the lower etchstop layer 130. The lower etch stop layer 130 is interposed between thelower interlayer insulating layer 110 and the upper interlayerinsulating layer 140. The lower etch stop layer 130 is interposedbetween the lower conductive pattern 120 p and the upper interlayerinsulating layer 140. The upper interlayer insulating layer 140 is incontact with the top surface of the lower etch stop layer 130.

The upper interlayer insulating layer 140 may have a different etch ratefrom the lower etch stop layer 130. The upper interlayer insulatinglayer 140 may have etch selectivity with respect to the lower etch stoplayer 130. The upper interlayer insulating layer 140 may include amaterial having a low dielectric constant. For instance, the upperinterlayer insulating layer 140 may include a low-k dielectric layer.

The upper interlayer insulating layer 140 includes an upper penetratinghole 140 h. The upper penetrating hole 140 h penetrates the upperinterlayer insulating layer 140. The upper penetrating hole 140 hexposes the lower penetrating hole 130 h. The upper penetrating hole 140h exposes the first recess region 121 r of the lower conductive pattern120 p.

A trench 140 t includes the first recess region 121 r, the lowerpenetrating hole 130 h, and the upper penetrating hole 140 h. A sidewallof the trench 140 t includes the sidewall of the lower penetrating hole130 h, a sidewall of the upper penetrating hole 140 h, and the sidewallof the first recess region 121 r. A level of a bottom surface of thetrench 140 t is substantially the same as a level of a bottom surface ofthe first recess region 121 r. The trench 140 t partially exposes thetop surface of the lower conductive pattern 120 p. The trench 140 tpenetrates the upper interlayer insulating layer 140.

The side spacers 160 s are disposed within the trench 140 t. A level oftop surfaces of the side spacers 160 s is substantially the same as alevel of a top surface of the upper interlayer insulating layer 140. Theside spacers 160 s are disposed on the top surface of the lowerconductive pattern 120 p. The side spacers 160 s are disposed on thebottom surface of the first recess region 121 r. The side spacers 160 sneed not vertically overlap the bottom surface of the second recessregion 122 r.

The side spacers 160 s are spaced apart from the sidewall of the trench140 t. The side spacers 160 s are spaced apart from the sidewall of thelower penetrating hole 130 h, the sidewall of the upper penetrating hole140 h, and the sidewall of the first recess region 121 r. The sidespacers 160 s are spaced apart from the bottom surface of the trench 140t. The side spacers 160 s are spaced apart from the bottom surface ofthe first recess region 121 r. A level of bottom surfaces of the sidespacers 160 s is higher than a level of the bottom surface of the firstrecess region 121 r. A level of the bottom surfaces of the side spacers160 s is higher than a level of the top surface of the lower conductivepattern 120 p.

The side spacers 160 s are disposed on a sidewall of the upperconductive pattern 170 p. The side spacers 160 s are in contact with theside surface of the upper conductive pattern 170 p. Each of the sidespacers 160 s includes a first side surface S1 and a second side surfaceS2.

The first side surface S1 of each of the side spacers 160 s is incontact with the side surface of the upper conductive pattern 170 p. Thefirst side surface S1 of each of the side spacers 160 s corresponds toan extension line of the sidewall of the second recess region 122 r.

The second side surface S2 of the side spacers 160 s is opposite to thefirst side surface S1 of the side spacers 160 s. The second side surfaceS2 of the side spacers 160 s faces the sidewall of the trench 140. Thesecond side surface S2 of each of the side spacers 160 s faces thesidewall of the lower penetrating hole 130 h and the sidewall of theupper penetrating hole 140 h.

The second side surface S2 of each of the side spacers 160 s may beparallel to the facing sidewall of the trench 140 t. The second sidesurface S2 of each spacer 160 s partially overlaps the lower penetratinghole 130 h and is parallel to the sidewall of the lower penetrating hole130 h. The second side surface S2 partially overlaps the upperpenetrating hole 140 h and is parallel to the sidewall of the upperpenetrating hole 140 h. A horizontal distance between the second sidesurface S2 and the sidewall of the lower penetrating hole 130 h issubstantially equal to a horizontal distance between the second sidesurface S2 and the sidewall of the upper penetrating hole 140 h.

The bottom surfaces of the side spacers 160 s are parallel to the bottomsurface of the first recess region 121 r. A vertical distance betweenthe bottom surface of each of the side spacers 160 s and the bottomsurface of the first recess region 121 r may be equal to the horizontaldistance between the second side surface S2 of each of the side spacers160 s and the sidewall of the first recess region 121 r. The verticaldistance between the bottom surface of each side spacer 160 s and thebottom surface of the first recess region 121 r may be substantiallyequal to the horizontal distance between the second side surface S2 ofeach of the side spacers 160 s and the sidewall of the lower penetratinghole 130 h. The vertical distance between the bottom surface of each ofthe side spacers 160 s and the bottom surface of the first recess region121 r may be equal to the horizontal distance between the second sidesurface S2 of each of the side spacers 160 s and the sidewall of theupper penetrating hole 140 h.

The side spacers 160 s may have a different etch rate from the upperinterlayer insulating layer 140. The side spacers 160 s may have an etchselectivity with respect to the upper interlayer insulating layer 140.The side spacers 160 s may include the substantially same material asthe lower etch stop layer 130. For example, the side spacers 160 s mayinclude SiCN.

The upper conductive pattern 170 p is electrically connected to thelower conductive pattern 120 p. The upper conductive pattern 170 p isdisposed within the trench 140 t. A level of a top surface of the upperconductive pattern 170 p is substantially the same as a level of the topsurface of the upper interlayer insulating layer 140. A level of the topsurface of the upper conductive pattern 170 p is substantially the sameas a level of the top surfaces of the side spacers 160 s. The upperconductive pattern 170 p is interposed between the side spacers 160 s.

A level of a bottom surface of the upper conductive pattern 170 p islower than a level of the bottom surfaces of the side spacers 160 s. Theupper conductive pattern 170 p is extended into the first recess region121 r of the lower conductive pattern 120 p. The upper conductivepattern 170 p is further extended into the second recess region 122 r ofthe lower conductive pattern 120 p. A level of the bottom surface of theupper conductive pattern 170 p is lower than a level of the bottomsurface of the trench 140 t. A level of the bottom surface of the upperconductive pattern 170 p is lower than a level of the bottom surface ofthe first recess region 121 r. The upper conductive pattern 170 p is incontact with the lower conductive pattern 120 p. A level of the bottomsurface of the upper conductive pattern 170 p is substantially the sameas a level of the bottom surface of the second recess region 122 r.

The upper conductive pattern 170 p completely fills the second recessregion 122 r. A horizontal width of the bottom surface of the upperconductive pattern 170 p is substantially equal to a horizontal width ofthe bottom surface of the second recess region 122 r.

The upper conductive pattern 170 p includes a barrier pattern 171 p anda metal pattern 173 p.

The barrier pattern 171 p covers side and bottom surfaces of the metalpattern 173 p. The barrier pattern 171 p is in contact with the sidespacers 160 s. The barrier pattern 171 p is in contact with the secondrecess region 122 r. The barrier pattern 171 p is in contact with thesidewall and bottom surface of the second recess region 122 r. Thebarrier pattern 171 p may include tantalum (Ta) or tantalum nitride(TaN). The barrier pattern 171 p may include a stack structure of a Tapattern and a TaN pattern.

The metal pattern 173 p is disposed in the barrier pattern 171 p. Theside and bottom surfaces of the metal pattern 173 p are surrounded bythe barrier pattern 171. The metal pattern 173 p may include a metalmaterial. For example, the metal pattern 173 may include copper (Cu).

The upper etch stop layer 180 is disposed on the upper interlayerinsulating layer. The upper etch stop layer 180 is disposed on the sidespacers 160 s. The upper etch stop layer 180 is disposed on the upperconductive pattern 170 p. The upper etch stop layer 180 is in contactwith the upper interlayer insulating layer 140, the side spacers 160 s,and the upper conductive pattern 170 p. A level of a bottom surface ofthe upper etch stop layer 180 is substantially the same as a level ofthe top surface of the upper interlayer insulating layer 140. A level ofthe upper etch stop layer 180 is substantially the same as a level ofthe top surfaces of the side spacers 160 s. A level of the upper etchstop layer 180 is substantially the same as a level of the top surfaceof the upper conductive pattern 170 p.

The upper etch stop layer 180 may have a different etch rate from theupper interlayer insulating layer 140. The upper etch stop layer 180 mayhave etch selectivity with respect to the upper interlayer insulatinglayer 140. The upper etch stop layer 180 may include substantially thesame material as the side spacers 160 s. For example, the upper etchstop layer 180 may include SIGN. The upper etch stop layer 180 may beharder than the side spacers 160 s.

The air gap 190 a is disposed within the trench 140 t. The air gap 190 ais interposed between the trench 140 t and the side spacers 160 s. Theair gap 190 a is interposed between the sidewall of the trench 140 t andthe second side surface S2 of each side spacer 160 s, and between thebottom surface of the trench 140 t and the bottom surface of each sidespacer 160 s. The air gap 190 a is extended along the sidewall andbottom surface of the trench 140 t. The air gap 190 a is interposedbetween the sidewall of the upper penetrating hole 140 h and the secondside surface S2 of each side spacer 160 s. The air gap 190 a isinterposed between the sidewall of the lower penetrating hole 130 h andthe second side surface S2. The air gap 190 a is interposed between thebottom surface of the first recess region 121 r and the bottom surfaceof each side spacer 160 s. The air gap 190 a is extended along thesidewall of the upper penetrating hole 140 h, the sidewall of the lowerpenetrating hole 130 h, and the top surface of the lower conductivepattern 120 p.

The air gap 190 a is defined by the lower conductive pattern 120 p, thelower etch stop layer 130, the upper interlayer insulating layer 140,the side spacer 160 s, the upper conductive pattern 170 p, and the upperetch stop layer 180. A lowest level of the air gap 190 a issubstantially the same as a level of the bottom surface of the firstrecess region 121 r of the lower conductive pattern 120 p. The lowestlevel of the air gap 190 a is substantially the same as a level of thebottom surface of the trench 140 t. A highest level of the air gap 190 ais substantially the same as a level of the bottom surface of the upperetch stop layer 180. The highest level of the air gap 190 a issubstantially the same as a level of the top surface of the upperinterlayer insulating layer 140. The highest level of the air gap 190 ais substantially the same as a level of the top surface of each of theside spacers 160 s The highest level of each of the air gaps 190 a issubstantially the same as a level of the top surface of the upperconductive pattern 170 p.

The air gap 190 a is extended along the top surface of the lowerconductive pattern 120 p to the side surface of the upper conductivepattern 170 p. The air gap 190 a exposes part of the side surface of theupper conductive pattern 170 p. The exposed part of the upper conductivepattern 170 p is disposed between the top surface of the lowerconductive pattern 120 p and the bottom surface of each of the sidespacers 160 s. The side surface of the upper conductive pattern 170 pmay be partially exposed by the air gap 190 a.

The side surface of the upper conductive pattern 170 p partially exposedby the air gap 190 a corresponds to the extension line of the sidesurface of the second recess region 122 r. The side surface of the upperconductive pattern 170 p partially exposed by the air gap 190 acorresponds to an extended boundary line between the upper conductivepattern 170 p and each side spacer 160 s. The side surface of the upperconductive pattern 170 p partially exposed by the air gap 190 a maycorrespond to an extension line of the first side surface S1 of eachside spacer 160 s. The sidewall of the second recess region 122 rcorresponds to the extension line of the first side surface S1 of eachof the side spacers 160 s.

In the semiconductor device according to an exemplary embodiment of theinventive concept, the air gap 190 a is interposed between the sidespacers 160 s of the upper conductive pattern 170 p and the trench 140t. For example, the side surface of the upper conductive pattern 170 pis surrounded by the air gap 190 a. Thus, capacitance between the upperconductive pattern 170 p and other adjacent conductive patterns may bereduced, thereby decreasing a signal delay time of the upper conductivepattern 170 p.

FIG. 2 is a cross-sectional view of a semiconductor device according toan exemplary embodiment of the inventive concept.

Referring to FIG. 2, a semiconductor device according to the embodimentsof the inventive concept includes a semiconductor substrate 100, a lowerinterlayer insulating layer 110, a lower conductive pattern 120 p, alower etch stop layer 130, an upper interlayer insulating layer 140,side spacers 160 s, an Upper conductive pattern 170 p, an upper etchstop layer 180, and an air gap 190 a.

The lower conductive pattern 120 p includes a first recess region 121 r.The first recess region 121 r is disposed in a top surface of the lowerconductive pattern 120 p. An upper penetrating hole 140 h of the upperinterlayer insulating layer 140 partially exposes a bottom surface ofthe first recess region 121 r.

A horizontal width w of each side spacer 160 s is less than a distancebetween a trench 140 t and the side spacer 160 s. The horizontal width wof each side spacer 160 s is less than a horizontal distance between theside spacer 160 s and a sidewall of the upper penetrating hole 140 h.The horizontal width w of each side spacer 160 s is less than ahorizontal distance between the side spacer 160 s and a sidewall of thelower penetrating hole 130 h of the lower etch stop layer 130. Thehorizontal width w of each of the side spacers 160 s is less than avertical distance between a bottom surface of each side spacer 160 s andthe bottom surface of the first recess region 121 r.

A level of a bottom surface of the upper conductive pattern 170 p issubstantially the same as a level of the bottom surface of the firstrecess region 121 r. A level of the bottom surface of the upperconductive pattern 170 p is substantially the same as a level of abottom surface of the trench 140 t. A level of the bottom surface of theupper conductive pattern 170 p is substantially the same as a level of alowest level of the air gap 190 a.

FIG. 3 is a cross-sectional view of a semiconductor device according toan exemplary embodiment of the inventive concept.

Referring to FIG. 3, a semiconductor device according to an exemplaryembodiment of the inventive concept includes a semiconductor substrate100, a lower interlayer insulating layer 110, a lower conductive pattern120 p, a lower etch stop layer 130, an upper interlayer insulating layer140, side spacers 160 s, an upper conductive pattern 170 p, an upperetch stop layer 180, and an air gap 190 a.

The lower conductive pattern 120 p includes a first recess region 121 r.A bottom surface of the upper conductive pattern 170 p is substantiallyat the same level as a bottom surface of the first recess region 121 r.A horizontal width w of each side spacer 160 s is less than a distancebetween a trench 140 t and the side spacer 160 s.

A horizontal width of a top surface of each side spacer 160 s is lessthan a horizontal width of a bottom surface thereof. A first sidesurface S1 of each side spacer 160 s includes a curved region 160 c thatis bent toward a second side surface S2 of each side spacer 160 s. Thecurved region 160 c is disposed close to the upper etch stop layer 180.

FIGS. 4A through 4R are cross-sectional views illustrating a method offabricating a semiconductor device according to an exemplary embodimentof the inventive concept.

A method of fabricating the semiconductor device according to anexemplary embodiment of the inventive concept will now be described withreference to FIGS. 1 and 4A through 4R. Referring to FIG. 4A, the methodof fabricating the semiconductor device according to an exemplaryembodiment of the inventive concept includes forming a lower interlayerinsulating layer 110, a lower conductive pattern 120 p, and a lower etchstop layer 130 on a semiconductor substrate 100.

The formation of the lower interlayer insulating layer 110, the lowerconductive pattern 120 p, and the lower etch stop layer 130 on thesemiconductor substrate 100 includes preparing the semiconductorsubstrate 100, forming the lower interlayer insulating layer 110 on thesemiconductor substrate 100, forming the lower conductive pattern 120 pon the semiconductor substrate 100, and forming the lower etch stoplayer 130 on the lower interlayer insulating layer 110 and the lowerconductive pattern 120 p.

Referring to FIG. 4B, an upper interlayer insulating layer 140 is formedon the lower etch stop layer 130.

The upper interlayer insulating layer 140 may include a material havinga different etch rate from the lower etch stop layer 130. For example,the upper interlayer insulating layer 140 may include a dielectric layerhaving a low dielectric constant.

Referring to FIG. 4C, a first mask pattern 410 is formed on the upperinterlayer insulating layer 140.

A preliminary first mask pattern layer is formed on the upper interlayerinsulating layer 140, and then the preliminary first mask pattern layeris patterned to form the first mask pattern 410 having a first mask hole410 h. The first mask hole 410 h exposes part of the upper interlayerinsulating layer 140. The first mask hole 410 h is disposed on a topsurface of the lower conductive pattern 120 p. The first mask pattern410 may include a photoresist pattern.

Referring to FIG. 4D, an upper penetrating hole 140 h is formed in theupper interlayer insulating layer 140 using the first mask pattern 410.

The upper penetrating hole 140 h partially exposes a top surface of thelower etch stop layer 130. The formation of the upper penetrating hole140 h includes etching the upper interlayer insulating layer 140 usingthe first mask pattern 410.

Referring to FIG. 4E, a trench 140 t is formed on the semiconductorsubstrate 100.

The formation of the trench 140 t includes forming a lower penetratinghole 130 h in the lower etch stop layer 130, and forming a first recessregion 121 r in the top surface of the lower conductive pattern 120 p.The trench 140 t includes the first recess region 121 r, the lowerpenetrating hole 130 h, and the upper penetrating hole 140 h. The trench140 t includes the first recess region 121 r, the lower penetrating hole130 h, and the upper penetrating hole 140 h.

The formation of the lower penetrating hole 130 h in the lower etch stoplayer 130 includes etching the lower etch stop layer 130 using the firstmask pattern 410.

The formation of the first recess region 121 r in the top surface of thelower conductive pattern 120 p includes recessing the top surface of thelower conductive pattern 120 p exposed by the lower penetrating hole 130h. The recessing of the top surface of the lower conductive pattern 120p exposed by the lower penetrating hole 130 h may be performedsimultaneously with a process of etching the lower etch stop layer 130using the first mask pattern 410.

Referring to FIG. 4F, the first mask pattern 410 is removed.

Referring to FIG. 4G, a sacrificial liner insulating layer 150 is formedon the upper interlayer insulating layer 140.

The formation of the sacrificial liner insulating layer 150 includescovering a sidewall and bottom surface of the trench 140 t with thesacrificial liner insulating layer 150. The formation of the sacrificialliner insulating layer 150 includes forming an insulating layer on thesidewall and bottom surface of the trench 140 t to a predeterminedthickness. The formation of the sacrificial liner insulating layer 150may be performed using an atomic layer deposition (ALD) process or aplasma-enhanced ALD (PEALD) process.

The sacrificial liner insulating layer 150 may include a material havinga different etch rate from the upper interlayer insulating layer 140.The sacrificial liner insulating layer 150 may have etch selectivitywith respect to the upper interlayer insulating layer 140. For example,the formation of the sacrificial liner insulating layer 150 may includeforming a silicon oxide (SiO) layer using a first silicon precursor. Thefirst silicon precursor may contain a silane-based material.

Referring to FIG. 4H, a spacer insulating layer 160 is formed on thesacrificial liner insulating layer 150.

The insulating layer is formed on a top surface of the sacrificial linerinsulating layer 150 in a predetermined thickness. The formation of thespacer insulating layer 160 may be performed using an ALD process or aPEALD process.

The spacer insulating layer 160 may include a material having adifferent etch rate from the sacrificial liner insulating layer 150. Thespacer insulating layer 160 may have etch selectivity with respect tothe sacrificial liner insulating layer 150. For example, the formationof the spacer insulating layer 160 may include forming a SiCN layer onthe sacrificial liner insulating layer 150 using a second siliconprecursor. The second silicon precursor may be a silane-based material.The second silicon precursor may be substantially the same material asthe first silicon precursor.

The process of forming the spacer insulating layer 160 may be performedin-situ together with the process of forming the sacrificial linerinsulating layer 150. For example, the semiconductor substrate 100having the trench 140 t may be loaded into a process chamber. The firstsilicon precursor may be supplied into the process chamber, and thesacrificial liner insulating layer 150 may be formed by reacting thefirst silicon precursor with oxygen plasma in the process chamber. Thefirst silicon precursor may be purged from the process chamber, and thenthe top surface of the sacrificial liner insulating layer 150 withnitrogen plasma. The second silicon precursor may be supplied into theprocess chamber, and the spacer insulating layer 160 may be formed byreacting the second silicon precursor with nitrogen plasma. The secondsilicon precursor may be purged from the process chamber.

The spacer insulating layer 160 and the sacrificial liner insulatinglayer 150 may be formed using an in-situ process. Thus, thicknessvariation of the sacrificial liner insulating layer 150 may be reduceddue to exposure to the atmosphere.

The nitrogen plasma may be generated using higher power than the oxygenplasma. For example, the oxygen plasma is generated using about 100 Wpower, and nitrogen plasma is generated using about 200 W power.

Referring to FIG. 4I, a planarization layer 210 is formed on the spacerinsulating layer 160.

The formation of the planarization layer 210 includes filling the trench140 t with the planarization layer 210. The planarization layer 210 mayinclude a material having high fluidity. For example, the planarizationlayer 210 may include forming the planarization layer 210 using SOH.

Referring to FIG. 4J, a second mask pattern 420 is formed on theplanarization layer 210.

The formation of the second mask pattern 420 may include forming apreliminary second mask pattern layer, and then patterning thepreliminary second mask pattern layer to form the second mask pattern420 having a second mask hole 420 h. The second mask hole 420 h exposespart of the planarization layer 210, and is disposed on a top surface ofthe lower conductive pattern 120. A horizontal width of the second maskhole 420 h is less than a horizontal width of the bottom surface of thetrench 140 t. For example, the horizontal width of the second mask hole420 h may be substantially equal to a maximum horizontal distancebetween sidewalk of the spacer insulating layer 160 disposed onsidewalls of the trench 140 t. The second mask pattern 420 may besubstantially similar to the first mask pattern 410. For example, thesecond mask pattern 420 may include a photoresist pattern.

Referring to FIG. 4K, a second recess region 122 r is formed in the topsurface of the lower conductive pattern 120 p formed on thesemiconductor substrate 100.

The formation of the second recess region 122 r may include forming aplanarization penetrating hole 210 h in the planarization layer 210,forming a spacer penetrating hole 160 h in the spacer insulating layer160, forming a liner penetrating hole 150 h in the sacrificial linerinsulating layer 150, and recessing the top surface of the lowerconductive pattern 120 p.

The formation of the planarization penetrating hole 210 h in theplanarization layer 210 may include etching the planarization layer 210using the second mask pattern 420.

The formation of the spacer penetrating hole 160 h in the spacerinsulating layer 160 may include etching the spacer insulating layer 160using the second mask pattern 420. The etching of the spacer insulatinglayer 160 using the second mask pattern 420 may be performedsimultaneously with the etching of the planarization layer 210 using thesecond mask pattern 420.

The formation of the liner penetrating hole 150 h in the sacrificialliner insulating layer 150 may include etching the sacrificial linerinsulating layer 150 using the second mask pattern 420. The etching ofthe sacrificial liner insulating layer 150 using the second mask pattern420 may be performed simultaneously with the etching of the spacerinsulating layer 160 using the second mask pattern 420.

The recessing of the top surface of the lower conductive pattern 120 pmay include recessing the top surface of the lower conductive pattern120 p exposed by the liner penetrating hole 150 h. The recessing of thetop surface of the lower conductive pattern 120 p exposed by the linerpenetrating hole 150 h may be performed simultaneously with the etchingof the sacrificial liner insulating layer 150 using the second maskpattern 420.

Referring to FIG. 4L, the second mask pattern 420 and the planarizationlayer 210 are removed.

Referring to FIG. 4M, the method of fabricating the semiconductor deviceaccording to an exemplary embodiment of the inventive concept mayinclude forming a barrier layer 171 on the spacer insulating layer 160.

The formation of the barrier layer 171 includes covering a sidewall ofthe spacer penetrating hole 160 h, a sidewall of the liner penetratinghole 150 h, and a sidewall and bottom surface of the second recessregion 122 r with the barrier layer 171.

Referring to FIG. 4N, a seed layer 172 is formed on the barrier layer171.

The formation of the seed layer 172 may include forming the seed layer172 using substantially the same material as a metal layer 173 to beformed using a subsequent process.

Referring to FIG. 4O, an upper conductive layer 170 is formed on theseed layer 172, filling a region surrounded by the trench 140 t.

The formation of the upper conductive layer 170 includes forming themetal layer 173 on the seed layer 172.

The formation of the metal layer 173 includes filling the spacerpenetrating hole 160 h, the liner penetrating hole 150 h, and the secondrecess region 122 r with the metal layer 173. The formation of the metallayer 173 includes filling a space between sidewalls of the spacerinsulating layer 160 disposed on the sidewalls of the trench 140 t withthe metal layer 173. The formation of the metal layer 173 may beperformed using an electroplating process.

Referring to FIG. 4P, a preliminary metal pattern 173 e is formed on thesemiconductor substrate 100.

The formation of the preliminary metal pattern 173 e includesplanarizing the metal layer 173 to expose a top surface of the barrierlayer 171. The planarization of the metal layer 173 may be performedusing a chemical mechanical polishing (CMP) process.

Referring to FIG. 4Q, a sacrificial liner pattern 150 s, a side spacer160 s, and an upper conductive pattern 170 p are formed on thesemiconductor substrate 100.

The formation of the sacrificial liner pattern 150 s, the side spacer160 s, and the upper conductive pattern 170 p includes planarizing thesacrificial liner insulating layer 150, the spacer insulating layer 160,the barrier layer 171, and the preliminary metal pattern 173 e to exposea top surface of the upper interlayer insulating layer 140. Theplanarization of the sacrificial liner insulating layer 150, the spacerinsulating layer 160, the barrier layer 171, and the preliminary metalpattern 173 e may be performed using a CMP process. The upper conductivepattern 170 p includes a barrier metal 171 p and a metal pattern 173 p.

The formation of the sacrificial liner pattern 150 s, the side spacer160 s, and the upper conductive pattern 170 p may be performed in thesame chamber as the process of forming the preliminary metal pattern 173e.

Referring to FIG. 4R, an air gap 190 a is formed in the trench 140 t.

The formation of the air gap 190 a in the trench 140 t includes removingthe sacrificial liner pattern 150 s.

The sacrificial liner pattern 150 s may include a material having adifferent etch rate from the upper interlayer insulating layer 140 andthe side spacer 160 s. Thus, the sacrificial liner pattern 150 s isselectively removed to form the air gap 190 a.

Forming of the sacrificial liner insulating layer 150 and the spacerinsulating layer 160 using an in-situ process, and forming thesacrificial liner pattern 150 s and the side spacer 160 s may reduce thenumber of processes required to form the sacrificial liner pattern 150 sand the side spacer 160 s, thereby increasing process efficiency.

Referring to FIG. 1, an upper etch stop layer 180 on the trench 140 t isformed to cover the air gap 190 a.

FIGS. 5A through 5G are cross-sectional views illustrating sequentialoperations of a method of fabricating a semiconductor device accordingto an exemplary embodiment of the inventive concept.

The method of fabricating the semiconductor device according to anexemplary embodiment of the inventive concept will now be described withreference to FIGS. 2 and 5A through 5G. To begin with, referring to FIG.5A, the method of fabricating the semiconductor device according to anexemplary embodiment of the inventive concept includes preparing asemiconductor substrate 100, forming a lower interlayer insulating layer110 on the semiconductor substrate 100, forming a lower conductivepattern 120 p on the semiconductor substrate 100, forming a lower etchstop layer 130 on the lower interlayer insulating layer 110 and thelower conductive pattern 120 p, forming an upper interlayer insulatinglayer 140 on the lower etch stop layer 130, forming a trench 140 tthrough the upper interlayer insulating layer 140, forming a sacrificialliner insulating layer 150 to cover a sidewall and bottom surface of thetrench 1401, and forming a spacer insulating layer 160 on thesacrificial liner insulating layer 150.

Referring to FIG. 5B, a first preliminary side spacer 161 s is formed onthe sacrificial liner insulating layer 150.

The formation of the first preliminary side spacer 161 s includesetching the spacer insulating layer 160. For example, the formation ofthe first preliminary side spacer 161 s may include anisotropicallyetching the spacer insulating layer 160.

The first preliminary side spacer 161 s includes a first preliminarycurved region 161 c. The first preliminary curved region 161 c may bedisposed close to a top surface of the first preliminary side spacer 161s.

Referring to FIG. 5C, a sacrificial spacer 151 s and a secondpreliminary side spacer 162 s are formed within the trench 140 t.

The formation of the sacrificial spacer 151 s and the second preliminaryside spacer 162 s may include etching the sacrificial liner insulatinglayer 150 and the first preliminary side spacer 161 s. For example, theformation of the sacrificial spacer 151 s and the second preliminaryside spacer 162 s may include anisotropically etching the sacrificialliner insulating layer 150 and the first preliminary side spacer 161 s.

The anisotropic etching of the sacrificial liner insulating layer 150and the first preliminary side spacer 161 s may be performedsimultaneously with the process of anisotropically etching the spacerinsulating layer 160. FIG. 5B may be a cross-sectional view of a shapeformed in the middle of the corresponding process.

The sacrificial spacer 151 s includes a sacrificial curved region 151 c.The sacrificial curved region 151 c is disposed close to a top surfaceof the sacrificial spacer 151 s.

The second preliminary side spacer 162 s includes a second preliminarycurved region 162 c. The second preliminary curved region 162 c isdisposed close to a top surface of the second preliminary side spacer162 s. A surface of the second preliminary curved region 162 c maycorrespond to an extension line of a surface of the sacrificial curvedregion 151 c. Alternatively, the surface of the second preliminarycurved region 162 c may have substantially the same curvature as thesurface of the sacrificial curved region 151 c.

Referring to FIG. 5D, a barrier layer 171 is formed on the upperinterlayer insulating layer 140.

The formation of the barrier layer 171 includes forming the barrierlayer 171 to cover the sacrificial spacer 151 s and the secondpreliminary side spacer 162 s.

Referring to FIG. 5E, the method of fabricating the semiconductor deviceaccording to an exemplary embodiment of the inventive concept mayinclude forming an upper conductive layer 170 to fill the trench 140 t.

The formation of the upper conductive layer 170 includes forming a metallayer 173 on the barrier layer 171.

Referring to FIG. 5F, a preliminary metal pattern 173 e is formed tofill the trench 140 t.

The formation of the preliminary metal pattern 173 e includesplanarizing the metal layer 173 to expose a top surface of the barrierlayer 171.

Referring to FIG. 50, a sacrificial liner pattern 150 s, a side spacer160 s, a barrier pattern 171 p, and a metal pattern 173 p are formed tofill the trench 140 t.

The formation of the sacrificial liner pattern 150 s, the side spacer160 s, the barrier pattern 171 p, and the metal pattern 173 p includesplanarizing the upper interlayer insulating layer 140, the sacrificialspacer 151 s, the second preliminary side spacer 162 s, the barrierlayer 171, and the preliminary metal pattern 173 e to remove thesacrificial curved region 151 c and the second preliminary curved region162 c. The planarization of the upper interlayer insulating layer 140,the sacrificial spacer 151 s, the second preliminary side spacer 162 s,the barrier layer 171, and the preliminary metal pattern 173 e isperformed using a CMP process.

An upper conductive pattern 170 p includes the barrier pattern 171 p andthe metal pattern 173 p.

Referring to FIG. 2, an air gap 190 a is formed in the trench 140 t byremoving the sacrificial liner pattern 150 s, and an upper etch stoplayer 180 is formed on the trench 140 t.

The formation of the air gap 190 a in the trench 140 t includes removingthe sacrificial liner pattern 150 s.

FIG. 6 is a diagram of a semiconductor module 1000 including asemiconductor device according to an exemplary embodiment of theinventive concept.

Referring to FIG. 6, the semiconductor module 1000 includes a modulesubstrate 1100, memories 1200, a microprocessor (MP) 1300, andinput/output (i/O) terminals 1400. The memories 1200, the MP 1300, andthe I/O terminals 1400 are mounted on the module substrate 1100. Thesemiconductor module 1000 may include a memory card or a card package.

Each of the memories 1200 and the MP 1300 may include a semiconductordevice according to an exemplary embodiment of the inventive concept.Accordingly, operation speeds of the memories 1200 and the MP 1300 maybe increased.

FIG. 7 is a diagram of a mobile system 2000 including a semiconductordevice according to an exemplary embodiment of the inventive concept.

Referring to FIG. 7, the mobile system 2000 includes a display unit2100, a body unit 2200, and an external apparatus 2300. The body unit2200 includes an MP 2210, a power supply 2220, a function unit 2230, anda display controller 2240.

The display unit 2100 is electrically connected to the body unit 2200.The display unit 2100 is electrically connected to the displaycontroller 2240 of the body unit 2200. The display unit 2100 displays animage processed by the display controller 2240 of the body unit 2200.

The body unit 2200 includes a system board or motherboard including aprinted circuit board (PCB). The MP 2210, the power supply 2220, thefunction unit 2230, and the display controller 2240 are mounted on thebody unit 2200.

The MP 2210 receives a voltage from the power supply 2230 and controlsthe function unit 2230 and the display controller 2240. The power supply2220 receives a predetermined voltage from an external power supply,divide the predetermined voltage into various voltage levels, and supplythe divided voltages to the MP 2210, the function unit 2230, and thedisplay controller 2240.

The power supply 2220 includes a power management IC (PMIC). The PMICefficiently supplies voltages to the MP 2210, the function unit 2230,and the display controller 2240.

The function unit 2230 serves various functions of the mobile system2000. For example, the function unit 2230 may include several elementscapable of wireless communication functions, such as output of an imageto the display unit 2100 or output of a voice to a speaker, by dialingor communication with the external apparatus 2300. For example, thefunctional unit 2230 may serve as an image processor of a camera.

When the electronic system 2230 is connected to a memory card toincrease the storage capacity of the mobile system 2000, the functionalunit 2230 serves as a memory card controller. In addition, when themobile system 2000 further includes a universal serial bus (USB) toexpand functions thereof, the functional unit 2230 may serve as aninterface controller.

Each of the MP 2210, the power supply 2220, and the function unit 2230includes a semiconductor device according to various exemplaryembodiments of the inventive concept. Accordingly, operation speeds ofthe MP 2210, the power supply 2220, and the function unit 2230 may beincreased,

FIG. 8 is a diagram of a mobile device 3000 including a semiconductordevice according to an exemplary embodiment of the inventive concept.

Referring to FIG. 8, the mobile device 3000 may be a mobile wirelessphone. Alternatively, the mobile device 3000 may be a tablet personalcomputer (PC). The mobile device 3000 may include a semiconductor deviceaccording to an exemplary embodiment of the inventive concept. Thus,operation speed of the mobile device 3000 according to an exemplaryembodiment of the inventive concept may be increased.

FIG. 9 is a construction diagram of an electronic system 4000 includinga semiconductor device according to an exemplary embodiment of theinventive concept.

Referring to FIG. 9, the electronic system 4000 includes a memory 4100,an MP 4200, a power supply 4300, and a user interface 4400. Theelectronic system 3000 may include a light-emitting diode (LED)illumination system, a refrigerator, an air conditioner, an industrialcutter, a welding machine, an automobile, a vessel, an airplane, or anartificial satellite.

The memory 4100 may store codes for booting the MP 4200, data processedby the MP 4200, or external input data. The memory 4100 may include acontroller and a memory.

The MP 4200 may program and control the electronic system 4000. The MP4200 may include a random access memory (RAM) used as an operationmemory.

The power supply 4300 may receive a predetermined voltage from anexternal power supply and supply appropriate voltages to the memory4100, the MP 4200, and the user interface 400 using the receivedvoltage. The power supply 4300 may include a PMIC.

The user interface 4400 may communicate data using a bus 4500. The userinterface 4400 may be used to input/output data to/from the electronicsystem 4000.

Each of the memory 4100 and the MP 4200 may include a semiconductordevice according to an exemplary embodiment of the inventive concept.Accordingly, operation speeds of the memory 4100 and the MP 4200 may beincreased.

According to an exemplary embodiment of the inventive concept, asemiconductor device may include a conductive pattern disposed within atrench formed through an interlayer insulating layer, side spacersdisposed on side surfaces of the conductive pattern, and an air gapinterposed between the trench and the side spacers. Thus, in asemiconductor device and a method of fabricating the same according toan exemplary embodiment of the inventive concept, a signal delay time ofthe conductive pattern may be reduced. Accordingly, in the semiconductordevice and the method of fabricating the same according to an exemplaryembodiment of the inventive concept, operation speed may be increased.

While the present inventive concept has been shown and described withreference to exemplary embodiments thereof, it will be apparent to thoseof ordinary skill in the art that various changes in form and detail maybe made therein without departing from the spirit and scope of theinventive concept as defined by the following claims.

What is claimed is:
 1. A semiconductor device comprising: asemiconductor substrate; a lower conductive pattern disposed on thesemiconductor substrate; an interlayer insulating layer disposed on thesemiconductor substrate, the interlayer insulating layer including anupper penetrating hole partially exposing a top surface of the lowerconductive pattern; an upper conductive pattern disposed within theupper penetrating hole and disposed on the top surface of the lowerconductive pattern, the upper conductive pattern electrically connectedto the lower conductive pattern; a side spacer disposed within the upperpenetrating hole, the side spacer covering an upper side surface of theupper conductive pattern; and an air gap disposed within the upperpenetrating hole, wherein the air gap is bounded by a sidewall of theupper penetrating hole, the side spacer, part of the top surface of thelower conductive pattern, and a lower side surface of the upperconductive pattern.
 2. The device of claim 1, wherein the lower sidesurface of the upper conductive pattern is not covered by the sidespacer.
 3. The device of claim 1, wherein a highest level of the air gapis substantially the same as a level of a top surface of the upperconductive pattern.
 4. The device of claim 1, wherein each of the sidespacer includes a first side surface being in contact with the upperside of the upper conductive pattern, and a second side surface facingthe sidewall of the upper penetrating hole, wherein the second sidesurface of each of the side spacer is extended in parallel to thesidewall of the upper penetrating hole.
 5. The device of claim 1,wherein a horizontal length of the air gap between a sidewall of theupper penetrating hole and a side surface of the side spacer issubstantially equal to a vertical length of the air gap between the topsurface of the lower conductive pattern and a bottom surface of the sidespacer.
 6. The device of claim 5, wherein the horizontal length of theair gap is greater than a horizontal width of the side spacer.
 7. Thedevice of claim 1, wherein the top surface of the lower conductivepattern includes a first recess region, wherein the first recess regioncorresponds to the part of the lower conductive pattern bounding the airgap.
 8. The device of claim 7, wherein a lowest level of the air gap issubstantially the same as a level of a bottom surface of the firstrecess region.
 9. The device of claim 7, wherein the top surface of thelower conductive pattern further includes a second recess region locatedat a center region of the top surface of the lower conductive pattern,wherein a level of a bottom surface of the second recess region is lowerhan a level of a bottom surface of the first recess region.
 10. Thedevice of claim 9, wherein a bottom portion of the upper conductivepattern covers sidewalls and a bottom of the second recess region. 11.The device of claim 9, wherein a level of a bottom surface of the upperconductive pattern is substantially the same as a level of the bottomsurface of the second recess region.
 12. The device of claim 11, whereina horizontal length of the bottom surface of the upper conductivepattern is substantially equal to a horizontal length of the bottomsurface of the second recess region.
 13. A semiconductor devicecomprising: a substrate including an interlayer insulating layer and atrench penetrating the interlayer insulating layer; a conductive patterndisposed within the trench of the substrate; a side spacer disposedwithin the trench, the side spacer covering an upper side surface of theconductive pattern; and an air gap disposed within the trench, the airgap being bounded by a sidewall of the trench, the side spacer, and alower side surface of the conductive pattern, wherein a level of abottom surface of the conductive pattern is lower than a level of bottomsurfaces of the side spacer.
 14. The device of claim 13, wherein a levelof the bottom surface of the conductive pattern is substantially thesame as a level of a lowest level of the air gap.
 15. The device ofclaim 14, wherein the bottom surface of the conductive pattern issubstantially the same as a level of a bottom surface of the trench. 16.A semiconductor device comprising: a semiconductor substrate; aninterlayer insulating layer disposed on the semiconductor substrate, theinterlayer insulating layer including a trench penetrating theinterlayer insulating layer; a conductive pattern disposed within thetrench, a bottom surface of the conductive pattern being in contact witha bottom surface of the trench; an etch stop layer disposed on theconductive pattern, the etch stop layer covering the trench; a sidespacer covering a side surface of the conductive pattern, the sidespacer being spaced apart from the interlayer insulating layer; and anair gap bounded by the interlayer insulating layer, the conductivepattern, the etch stop layer and the side spacer, wherein a bottomsurface of the side spacer is spaced apart from the bottom surface ofthe trench.
 17. The device of claim 16, wherein a level of a bottomsurface of the etch stop layer is substantially the same as a level of atop surface of the interlayer insulating layer, and wherein the bottomsurface of the etch stop layer is in contact with a top surface of theconductive pattern and a top surface of the side spacer.
 18. The deviceof claim 16, wherein the vertical length between the bottom surface ofthe side spacer and the bottom surface of the trench is substantiallyequal to a horizontal width of the side spacer.
 19. The device of claim18, wherein the horizontal width of the side spacer is substantiallyequal to a horizontal length between a side surface of the side spacerand a sidewall of the trench.
 20. The device of claim 18, wherein avertical length of a lower side surface of the upper conductive patternwhich is not covered by the side spacer is greater than the verticallength between the bottom surface of the side spacer and the bottomsurface of the trench.